multi threading a web application

Question

I know there are many cases which are good cases to use multi-thread in an application, but when is it the best to multi-thread a .net web application?

Answer 1

Multithreading is a technique to provide a single process with more processing time to allow it to run faster. It has more threads thus it eats more CPU cycles. (From multiple CPU's, if you have any.) For a desktop application, this makes a lot of sense. But granting more CPU cycles to a web user would take away the same cycles from the 99 other users who are doing requests at the same time! So technically, it's a bad thing.

However, a web application might use other services and processes that are using multiple threads. Databases, for example, won't create a separate thread for every user that connects to them. They limit the number of threads to just a few, adding connections to a connection pool for faster usage. As long as there are connections available or pooled, the user will have database access. When the database runs out of connections, the user will have to wait.

So, basically, the use of multiple threads could be used for web applications to reduce the number of active users at a specific moment! It allows the system to share resources with multiple users without overloading the resource. Instead, users will just have to stand in line before it's their turn.

This would not be multi-threading in the web application itself, but multi-threading in a service that is consumed by the web application. In this case, it's used as a limitation by only allowing a small amount of threads to be active.